Electron probe microanalysis (EPMA) is a method for directing a sharply focused electron beam at a specimen surface, dispersing characteristic X-rays emanating from the irradiated surface by the use of an analyzing crystal and detecting the dispersed X-rays by an X-ray detector to analyze the elements contained in the specimen. Such characteristic X-rays are some of K, L, M lines, etc., depending on the element. The K family includes numerous line species such as K.alpha..sub.1, K.alpha..sub.2, . . . , K.beta..sub.1, etc. In electron probe microanalysis where X-rays are spectrally dispersed through the use of an analyzing crystal, X-rays due to higher-order reflections such as 2nd-, 3rd- and 4th-order lines are observed, as well as the 1st-order line produced by the 1st-order reflection, because of the nature of spectral dispersion by the analyzing crystal. Therefore, many characteristic X-ray line peaks are often observed to overlap each other on the X-ray spectrum.
The operator performs the following steps as one method of examining what elements are contained in the specimen. The operator watches the obtained X-ray spectrum on the chart and estimates the presence of one element. The element should be present at some location on the spectrum. Then, he or she examines X-ray line peaks observed near this location and judges whether this element is present. When some element is specified, if some markers indicating the positions at which the characteristic X-rays emitted from the element should appear are displayed on the spectrum, then convenience is offered. An energy-dispersive X-ray spectrometer (EDS) attached to a scanning electron microscope (SEM) has heretofore used KLM markers. Therefore, the function of these KLM markers may be applied to the electron probe microanalyzer. However, electron probe microanalysis has higher-order lines and better wavelength resolution than energy-dispersive X-ray spectrometry. Therefore, more line species are detected. Consequently, if data about higher-order lines are simply added to the KLM markers for EDS, the following problems take place.
FIG. 5 is a diagram representing an example of display of such KLM markers. X-ray spectra collected by EPMA are observed to contain numerous line species and characteristic X-rays of various orders for each element. Where plural elements are specified and their respective KLM markers are displayed, it follows that numerous markers denoting the characteristic X-rays emanating from the elements are intermingled. Therefore, the markers for the characteristic X-rays originating from the element of interest are not easy to discern or recognize.